In a bowl, mix cream cheese and mustard until smooth.
Place 3 slices of bread on your worktop. Spread each with a thin layer of the cream cheese mixture (you should use about ½ of it).
Now, take 2 slices of cheddar and place these on top of one slice. Add 1 or 2 slices of ham (see note 4) and top this with lettuce. Cover with second slice of bread and top this again with cheese (I only use 1 slice here), ham, lettuce and the last slice of bread (spread side facing down). Press down slightly. Repeat the same with the other 3 slices.
Cut each sandwich in half. Stick 6 toothpicks into each half and cut around them. You will get 6 mini sandwiches out of 1 half = 12 mini sandwiches out of 1 sandwich (check the process pictures for better understanding). Sticking the toothpicks in before cutting keeps the fillings from moving and makes it easier to cut the tiny sandwiches.
Transfer them onto a serving tray and enjoy!
Notes
Mustard - again, use any mustard you like. I used classic French mustard.
Bread - I used crustless white bread. You can buy any bread you like - can be with crust and you will remove it yourself. It can also be wholegrain.
Any sliced cheese will work here. My favorite is red cheddar. Mozzarella or Gouda or Edam are also delicious choices.
Our local supermarket sells very thinly sliced ham (almost paper-thin). If you buy a thick ham, I suggest using only 1 slice per layer instead of 2.
Baby lettuce leaves - I buy the packaged ready-to eat mixed leaves, You can also use other lettuce, if you like.
24 mini sandwiches are ready in 10 minutes so they are very quick to make, but if you would like to prepare them ahead, you will need to store them in an air-tight container in the fridge. Otherwise, the top bread layer will dry out. You could prep them the night before, but I recommend only a few hours for the best results.